Methylobacterium as a Dual-Function Platform: Advances in C₁-Based Biomanufacturing and Plant-Associated Applications

One-carbon (C₁) substrates are promising feedstocks for microbial bioproduction. Methylobacterium, known for its exceptional C₁ utilization capacity, has emerged as a model microbial chassis for sustainable biomanufacturing. In this review, we first outline the C₁ assimilation pathways in Methylobacterium and underscore its potential for producing valuable native metabolites. Furthermore, we then survey the genetic tools available for engineering this genus, including plasmid-based methods, transposon mutagenesis, homologous recombination, and CRISPR/Cas systems. Notably, recent advances in metabolic engineering have significantly expanded its biosynthetic scope, enabling the biosynthesis of diverse non-native compounds. Beyond its biomanufacturing potential, Methylobacterium also serves as a versatile plant growth-promoting bacterium, enhancing plant health and productivity through hormone synthesis, nutrient mobilization, stress mitigation, and induced systemic resistance. Collectively, this work highlights the dual potential of Methylobacterium as a sustainable microbial cell factory for biomanufacturing and a beneficial bioinoculant for agriculture.